1. Field of the Invention
This invention belongs to the field of seats for a transport vehicle. It relates more particularly to a device for absorbing the energy of a seat in the event of high acceleration and a seat comprising such a device intended to be installed in a vehicle that can experience high accelerations.
The invention is applicable in particular aboard aircraft, to absorb energy in the event of acceleration connected with a crash.
2. Description of the Related Art
In the field of the transport of persons, in particular in air transport, the accelerations caused by a crash can reach levels that are barely tolerable for a person. It is known to limit the value of the maximum acceleration experienced by a person aboard an aircraft by absorbing a portion of the energy applied to the seat on which this person is located.
According to a known method, for example from the document U.S. Pat. No. 4,440,441, the deformation of the structures of the seat is used to absorb energy in the event of a crash.
In this case, it is necessary to design the structure of the seat so that it is deformed in a suitable manner and so that the structure remains sufficiently strong to hold the passenger. The design regulations are in this case very restrictive.
According to another known method, for example from the document U.S. Pat. No. 3,985,388, the seat pan of the seat is attached, with a possibility of shifting in an assumed direction of the acceleration in the event of a crash, to a rigid structure using energy-absorbing elements during a shifting of the seat pan by plastic deformations of elements for connecting the seat pan to the rigid structure or dampers that function after the breaking of a shear pin element.
These various known solutions to limit the accelerations experienced in the event of a crash exhibit the drawback of leading to irreversible deformations, and, as a consequence, the means that absorb the energy cannot be tested individually and then placed back in operation.
Furthermore, the energy to be absorbed in the event of acceleration is a function of the mass of the seat with its occupant. Taking into account that all possible occupants of a seat do not necessarily have the same weight, the energy absorption devices are most often a compromise between the weight of the lightest passenger envisaged and that of the heaviest, which poses problems both for the maximum value of the acceleration experienced, higher for the lightweight occupant, and for the amplitude of the movement during which the acceleration is experienced, greater for a heavy occupant. Such a solution is therefore appropriate only partially and imperfectly in the extreme cases.
Solutions for matching the energy absorber to the weight of the occupant of the seat, such as, for example, the solution described in the document U.S. Pat. No. 7,921,973, are generally complex and therefore more costly and less reliable.